Sachs 125 Motocross
THE ULTIMATES:SACHS 125 MOTOCROSS
Five-Speed Fun for Novice or Champion
SACHS MOTORS of Germany, supplier of motorcycle engines to a great many manufacturers the world over, has stepped into competition with a new creation of its own-the 125 Sachs Motocross. Although especially designed for motocross racing, the 125 Sachs is readily adaptable to all forms of off-road entertainment. It is an ideal recreation bike for the enthusiastic novice inside whose helmet are bright visions of future motocross competition.
The 125 Motocross model is accompanied by a smaller stable mate, a 100-cc machine called the Cross Country. The pair supersedes the previous model K80GS, which has been discontinued.
The 125 Sachs can be characterized as a go-anywhere machine, invested with the flexibility that only years of experience in International Six Day Trials competition can produce. Sachs experience has resulted in a motorcycle of extreme light weight and lightfooted agility.
Thus, it is surprising that a motocross machine of the Sachs’ quality has not yet met with overwhelming popularity. Perhaps the bike’s rather unorthodox appearance accounts for this apparent lack of broad acceptance. Judgment of this bike on looks alone is a definite mistake. The Sachs 125 Motocross can’t be seriously faulted with respect to overall performance.
The machine comes out of the crate ready to compete—there’s no need to pay for and install high performance components. The engine already is race tuned, a racing exhaust system is fitted, and motocross tires are installed front and rear.
With bore and stroke square at 54 mm, the Sachs engine’s piston displacement actually is 123 cc. In competition configuration, the piston ported twostroke Single develops a claimed 15.5 bhp at 7500 rpm, and performance substantiates this claim. Power development starts well down in the rpm range, and continues to build strongly up to the rpm limit. No tachometer is fitted, but this isn’t missed because the engine’s strength in the mid-rpm range reduces the necessity for the rider to wing the engine to higher rpm ranges.
Carburetion is by a 24-mm Bing concentric, of West German manufacture. Induction is through a shrouded air filter and a clear plastic pipe which runs through a 3-in. hole in the frame backbone tube. Ignition is by Bosch magneto.
The engine is in-unit with a five-speed gearbox, internal ratios of which, first to fifth respectively, are 4.60:1, 2.73:1, 1.95:1, 1.50:1 and 1.24:1. Final drive is through single row chain.
Though very little technical information presently is available on the Sachs 125 Motocross, it can be assumed the firm will supply a variety of sprockets to alter overall ratios to suit specific competition conditions.
The engine/gearbox unit is suspended from two mounting points under the large diameter backbone tube, which extends from steering head to just below the swinging arm pivot—a layout similar to earlier Sachs motocross models.
The high level exhaust system, painted black for better heat dissipation, is mounted on the right-hand side of the machine, well clear of the rider’s leg. During test riding, the tailpipe stub disappeared, perhaps for reasons of weld metal fatigue induced by two-stroke vibration, but the inadvertent “detuning” in no way affected the performance of the 125 Motocross.
The 125 engine produces considerably greater power and torque reaction through the frame than did the K80GS powerplant. For this reason, two small diameter forward downtubes, that run underneath the engine/gearbox to a point below the swinging arm pivot, have been added. These, secured to the crankcase on either side, supply additional frame rigidity to combat torsional stress.
A boxlike structure at the lower extremity of the backbone provides anchor points for the swinging arm pivot, engine mounts, and the pair of smaller diameter downtubes. From the box member, a triangular subframe extends rearward on each side of the rear wheel to support the rear suspension units, seat and rear fender.
The rear suspension itself is by coil springs, damped by telescopic shock absorbers. Travel of 4.5 in. is provided. If this appears conventional, the front suspension is something out of the ordinary. Forward is an Earles-type leading link fork assembly which provides 6 in. of wheel travel over off-road irregularities.
Brakes are more than adequate; on loose surfaces, care must be exercised or the front wheel will lock with untoward suddenness.
The 125 Sachs Motocross is finished in black with chrome-plated panels on each side of the gold painted fuel tank. Cylinder head and barrel also are finished in black—both for better heat dissipation and businesslike appearance. Crankcase and timing cover castings are rather squared-off, which contributes to the no-nonsense mein of the bike; and the cases are finished with craftsmanship that usually is expected with more expensive machinery.
The basic 125 Sachs is supplied without lights, but provision is made for quick attachment of 6-V lighting equipment to the magneto/generator.
To take the machine onto the trails, into the woods is a delight. The 125 engine starts with ridiculous ease. One gentle kick and the engine fires—always. And handling is equally as difficult to fault. Gear changes are effortless, yet positive, but in over anxiety it is possible to overshift through permissive pedal travel. As with other motorcycles of relatively low bhp, as compared to larger motocross machines, the rider must employ a slightly different riding technique to extract the machine’s ultimate capabilities. Acceleration from corners must be late and hard. The Sachs’ gearbox assists here. The rider is able to select an ideal gear for each corner and thus can utilize all 15.5 bhp to execute his rapid exodus. And, with careful throttle manipulation, these changes can be made quickly without use of the clutch—though this isn’t recommended practice.
Furthermore, the Sachs 125 is probably the world’s fastest motorcycle-downhill. The machine possesses an inherent stability and jounce/ rebound damping facility that gives it the ability to absorb all cross country rough stuff—short of the Grand Canyon. The Sachs can be hurtled down inclines that never will be traversed by heavier, faster, larger displacement machines.
This magnificent suspension system is not without problems—not faults, problems. Under heavy braking the Earlestype front suspension lifts the front end of the machine, the reverse of what occurs with a telescopic fork equipped motorcycle that dips under braking. Once this strange reversal is detected, it is easily taken into account, and the Sachs becomes a most delightful motocross machine.
In any discussion of ride and handling, comfort must come under consideration. Foot and handlebar controls are located with an eye to convenience, but the handlebar itself is a source of major complaint. That component harks back to its rearward sweeping counterpart on Granddad’s bike, or on the California desert sled which riders ride, rather than stand upon, as is motocross practice. The Sachs handlebar pushes the rider farther rearward than is desirable for truly precise handling. Because of the odd handlebar shape, a slide can easily be induced while riding the Sachs 125. Care must be exercised.
In another respect, the handlebar generates discomfort. For more serious, and more comfortable, motocross competition, a straighter, wider handlebar is mandatory. That handlebar would control those slides.
To sum up, the 125 Sachs Motocross offers horsepower, flexibility, strength and the high degree of handling quality that can make the machine an outstanding performer in its competition class. There’s one additional factor that makes this motorcycle a winner. The price, p.o.e., is $578. fo]
